Range Selector Displays Incorrect Range

Range Selector Displays Incorrect Range





Circuit Description

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The 4 inputs to the TCM indicate the position of the transmission range selector. The input voltage level at the TCM is high, B+, when the IMS is open and low when the switch is closed to ground. The 4 input parameters represented are Signals A, B, C and P, Parity. Refer to Transmission Internal Mode Switch Logic.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
2. HI values for all signals in all ranges indicates the ground circuit is OPEN.
3. With the 20-way connector disconnected, all signals should indicate HI.
5. If a circuit affects the other, this indicates a short between the 2 circuits.
11. This step tests the internal transmission harness. If no fault is found in the harness, the fault will be in the switch.

Step 1 - Step 6:

Step 7 - Step 13:

Step 14 - Step 17: